ARTICLE | doi:10.20944/preprints201807.0034.v2
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: multi-objective optimization; resource efficiency; metal mines; production process; NSGA-II
Online: 29 November 2018 (10:59:56 CET)
The optimization of the production process of metal mines has been traditionally driven only by economic benefits while ignoring resource efficiency. However, it has become increasingly aware of the importance of resource efficiency since mineral resource reserves continue to decrease while the demand continues to grow. To better utilize the mineral resources for sustainable development, this paper proposes a multi-objective optimization model of the production process of metal mines considering both economic benefits and resource efficiency. Specifically, the goals of the proposed model are to maximize the profit and resource utilization rate. Then, the fast and elitist Non-Dominated Sorting Genetic Algorithm (NSGA-II) is used to optimize the multi-objective optimization model. The proposed model has been applied to the optimization of the production process of a stage in the Huogeqi Copper Mine. The optimization results provide a set of Pareto-optimal solutions that can meet varying needs of decision makers. Moreover, compared with those of the current production indicators, the profit and resource utilization rate of some points in the optimization results can increase respectively by 2.99% and 2.64%. Additionally, the effects of the decision variables (geological cut-off grade, minimum industrial grade and loss ratio) on objective functions (profit and resource utilization rate) were discussed using variance analysis. The sensitivities of the Pareto-optimal solutions to the unit copper concentrate price were studied. The results show that the Pareto-optimal solutions at higher profits (with lower resource utilization rates) are more sensitive to the unit copper concentrate prices than those obtained in regions with lower profits.
ARTICLE | doi:10.20944/preprints202305.2154.v1
Subject: Computer Science And Mathematics, Computer Vision And Graphics Keywords: VISLAM; dynamic environments; object detection; geometric constraint; IMU prior constraint
Online: 30 May 2023 (13:29:38 CEST)
Visual inertial SLAM algorithms enable robots to autonomously explore and navigate in unknown scenes. However, most of the current SLAM systems highly rely on static environment assumptions, which fails in the exsitence of motional objects in the real environment. To improve the robustness and localization accuracy of SLAM systems in dynamic scenes, this paper proposes a visual-inertial SLAM framework that fuses semantic and geometric information, called DA-VINS. First, this paper presents a dynamic object classification method based on feature’s current motion state, which obtains temporary static features in the environment. Secondly, a features dynamics check module based on IMU prior and adjacent frame’s geometry constraint is designed to calculate dynamic factors. It also verifies the classification results of temporary static features. Finally, a dynamic adaptive bundle adjustment module based on the features’ dynamic factors is designed to adjust the weights of features in nonlinear optimization. We evaluated our method in public and our dataset. The results show that D-VINS is one of the most real-time, accurate, and robust systems in dynamic scenes.
ARTICLE | doi:10.20944/preprints202302.0059.v1
Subject: Biology And Life Sciences, Biophysics Keywords: hSERT; comprehensive molecular dynamics (MD) simulation; drug design; MM/GBSA
Online: 3 February 2023 (06:16:06 CET)
The human serotonin transporter (hSERT) terminates neurotransmission by removing serotonin from the synaptic cleft, which is an essential process plays an important role in depression. In addition to substrate serotonin, hSERT is also the target of drugs of abuse like cocaine and clinically used antidepressants such as escitalopram and paroxetine. To date, few studies attempt to investigate the unbinding mechanism underlying the orthosteric and allosteric modulation of hSERT. The high-resolution X-ray structure of hSERT resolved recently enables us to theoretically study the unbinding of the above four ligands against the S1 or S2 site of hSERT, by means of molecular docking, molecular dynamics (MD) and potential of mean force (PMF) simulations. We proved that for either the S1 or S2 site, the other three ligands (cocaine, escitalopram and paroxetine) are much more favorable than the original substrate serotonin, whether in kinetics along the unbinding pathways or in thermodynamics at the equilibrium states. Furthermore, the S1 site is much more favorable than the S2 site, for each ligand. Interestingly, inspection revealed that there are ~ 3Å lengths between the allosteric site of serotonin and cocaine, and an unseen un-binding pathway for escitalopram at the S1 site except for verification of the broadest trail.
ARTICLE | doi:10.20944/preprints202308.1451.v1
Subject: Biology And Life Sciences, Other Keywords: Genetics and Genomics; Evolutionary Biology; Zoology
Online: 22 August 2023 (03:43:10 CEST)
The Oriental ratsnake Ptyas mucosa is a common non-venomous snake of the colubrid family, with a wide geographic range spanning much of South and Southeast Asia. P. mucosa is widely cultivated dut to it used in traditional medicine, scientific research, and handicrafts. Therefore, genome resources could play an important role in the efficacy of traditional medicine and the analysis of the living environment of the species. We collected a snake sample in Hezhou, Guangxi, China, which was identified as P. mucosa by morphological identification. Here we present a highly continuous P. mucosa genome with a genome size of 1.74Gb. The scaffold N50 length is 9.57Mb and the maximal length of scaffold is 78.3Mb, the P. mucosa genome has a CG content of 37.9% and the integrity of the gene reached 86.6%.Assembled using long-reads, the total length of the repeat sequence in the genome reached 735 Mb, and its repeat content was as high as 42.19%. A total of 24,869 functional genes were annotated. This study will assist in the understanding of the P. mucosa, and also provide a basis for medicinal research.
ARTICLE | doi:10.20944/preprints202310.1150.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: FAU membrane; zeolite; secondary growth; gas separation; propylene propane separation; H2/C3H8 separation
Online: 19 October 2023 (04:40:36 CEST)
In this study, high-performance FAU (NaY type) zeolite membranes were successfully synthesized using small-sized seeds of 50 nm, and their gas separation performance was systematically evaluated. Employing nano-sized NaY seeds and an ultra-dilute reaction solution with a molar composition of 80 Na2O: 1Al2O3: 19 SiO2: 5000H2O, the effects of synthesis temperature, crystallization time, and porous support (α-Al2O3 or mullite) on the formation of FAU membranes were investigated. The results illustrated that further extending the crystallization time or increasing the synthesis temperature led to the formation of a NaP impurity phase on the FAU membrane layer. The most promising FAU membrane with a thickness of 2.7 µm was synthesized on an α-Al2O3 support at 368 K for 8 h, and had good reproducibility. The H2 permeance of the membrane was as high as 5.34×10-7 mol/(m2 s Pa), and the H2/C3H8 and H2/i-C4H10 selectivities were 183 and 315, respectively. The C3H6/C3H8 selectivity of the membrane was as high as 46 with a remarkably high C3H6 permeance of 1.35× 10-7 mol/(m2 s Pa). The excellent separation performance of the membrane is mainly attributed to the thin, defect-free membrane layer and relatively wide pore size (0.74 nm).
ARTICLE | doi:10.20944/preprints202111.0313.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: PRDX6; inflammation; NRF2; HGFs.
Online: 17 November 2021 (23:34:15 CET)
Periodontitis is a progressive and inflammatory oral disease and results in the damage of the supporting tissues of teeth. Peroxiredoxin6 (PRDX6) is an antioxidant enzyme and has been identified as a regulator in redox balance. This study aimed to investigate whether PRDX6 could protect human gingival fibroblasts (HGFs) from lipopolysaccharide (LPS) induced inflammation and its mechanisms. Here, both inflamed and non-inflamed human gingival tissues were collected to assess the expression of PRDX6 and NRF2 by Immunohistochemistry and Western blotting. Furthermore, HGFs were stimulated with LPS, MJ33 (PRDX6 phospholipase A2 inhibitor), or ML385 (NRF2 inhibitor). The expression levels of inflammatory cytokines were measured by RT-qPCR and ELISA, and reactive oxygen species (ROS) was detected using DCFH-DA. PRDX6 was downregulated in inflamed gingival tissues. In HGFs, LPS induced inflammatory cytokines and ROS was upregulated in PRDX6 knockdown cells. Furthermore, co-treatment with MJ33 alleviated LPS-induced inflammatory cytokines and ROS, while inhibiting NRF2 upregulated those in HGFs. Therefore, this study provided a new mechanistic insight that PRDX6, regulated by the NRF2 signaling, alleviates LPS- induced periodontitis in human gingival fibroblasts.
ARTICLE | doi:10.20944/preprints202307.0733.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: tomato; Sly-miR171d/e; short tandem target mimic (STTM); salt stress; fruit quality
Online: 11 July 2023 (12:38:29 CEST)
High salinity in soil affects the normal growth and development of crop. MicroRNA171 (miR171) plays a momentous role in plant resistance to adversity stress. The functions of Sly-miR171d and Sly-miR171e on growth of tomato and fruit nutritional quality under salt stress were studied. The results showed that the seed germination and seedling growth of tomato that silencing of Sly-miR171d/e by short tandem target mimic (STTM) were better than those of wild-type (WT). Silencing of Sly-miR171d/e seeds maintained a high germination rate, while WT tomato seeds barely germinated under 50 mM NaCl stress. Under 100 mM NaCl stress, silencing of Sly-miR171d/e increased the expression of their target gene SlGRAS24 with increasing duration of salt stress, while they enhanced the antioxidant activity, reduced reactive oxygen species (ROS) accumulation, and enhanced the salt tolerance of tomato plant by regulating gibberellin (GA) level. Moreover, the preharvest and postharvest fruit nutritional quality under salt stress was also studied, and the results showed that silencing of Sly-miR171d/e increased soluble solids, lycopene, total carotenoids, Vitamin C, organic acids and phenolic substances in tomato fruit. The present study demonstrated that silencing of Sly-miR171d/e enhanced plant salt tolerance through the GA pathway, and improved fruit nutritional quality under salt stress.
ARTICLE | doi:10.20944/preprints202309.1954.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Fusarium tricinctum; Trichothecium roseum; chalcone; cyanide-resistant respiration; alternative oxidase
Online: 28 September 2023 (07:12:37 CEST)
Chalcones are a class of flavonoids possessing a variety of biological activities, including antimicrobial and antioxidant effects. Therefore, chalcones and their derivatives have potential use in the control of postharvest diseases. In this work, the effects of 2ʹ,4ʹ-dichloro-chalcone on the in vitro growth and in vivo pathogenicity of F. tricinctum and T. roseum were investigated. The results showed that 100 µM of 2ʹ,4ʹ-dichloro-chalcone strongly inhibited mycelial growth and conidial production of F. tricinctum (32.3%) and T. roseum (65.2%) in vitro. This treatment also significantly inhibited the expansion of potato dry rot from F. tricinctum (48.6%) and apple rot spot from T. roseum (36.2%). The incubation of F. tricinctum and T. roseum conidia with this agent for 2 h increased their cell membrane permeability by 25% and 22.5%, respectively and conidial membrane permeability by 41.7 and 65.4%, respectively. This treatment also significantly inhibited the total respiration rate and activated the cyanide-resistant respiratory pathway in both pathogens. Protein immunoblotting showed that the treatment increased alternative oxidase (AOX) levels after 4 h in F. tricinctum and T. roseum by 52.76% and 39.13%, respectively. Conclusion: 100 µM 2ʹ,4ʹ-dichloro-chalcone significantly inhibited mycelial growth and spore production in F. tricinctum and T. roseum in vitro and reduced their pathogenicity in postharvest potato and apple crops. Further analysis indicated that 2ʹ,4ʹ-dichloro-chalcone disrupted the integrity of cell membranes and the mitochondrial respiratory electron transport chain which leaded to ROS burst and oxidative stress, AOXs were induced directly or indirectly, and the cyanide resistant respiratory pathway was activated. The in vitro growth and pathogenicity of F. tricinctum and T. roseum were inhibited.
ARTICLE | doi:10.20944/preprints201701.0019.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: high-entropy alloys; Al-Ni-Co-Fe-Cr alloys; microstructure; precipitation morphology; mechanical property
Online: 4 January 2017 (10:30:17 CET)
The present work investigates primarily the morphology evolution of the body-centered-cubic (BCC)/B2 phases in AlxNiCoFeCr high-entropy alloys (HEAs) with increasing Al content, which has been neglected so far. There exist two types of microscopic morphologies of BCC and B2 phases in this HEA series: one is the weave-like morphology induced by the spinodal decomposition, and the other is the microstructure of a spherical disordered BCC precipitation on the ordered B2 matrix that appears in HEAs with a much higher Al content. The shape of coherent precipitates is found to be closely related to the lattice misfit between BCC and B2 phases, which is sensitive to Al. The mechanical properties, including the compressive yielding strength and microhardness of the AlxNiCoFeCr HEAs, are also discussed in light of the concept of the valence electron concentration (VEC).